Method of sulfurizing esters



rid-3 an i Patented July 7, 1 953 METHOD OF SULFURIZING ESTERS Helen Sellei Beretvas; Chicago, 11]., assignorto Standard Oil Company, Chicago, 111., a corporat tion of Indiana No Drawing. Application June 29, 1949, Serial No. 102,170

20 claims. (01. 260-97 5) The present invention relates to improvements in the sulfur'mation of unsaturated esters of aliphatic acids, and more particularly is directed to improvements in the sulfurization of unsaturated mono-esters of aliphatic acids with sulfur chloride.

Mono-esters of aliphatic acids have been sulfurized with a sulfur chloride, such as SzCl-z. However, in the prior methods the sulfurized products obtained were usually dark in color. In order to obtain a product of good color, it has been the usual practice to carry out the sulfurization at relatively low temperatures and by carefully controlling the rate of addition of the reactants. The slow addition of the reactants at relatively low temperatures made the process 1 long and tedious, requiring careful controlled conditions. For example, in the method described in U. S. Patent No. 2,179,062, issued to El. G. Smith et a1. November 7, 1939, the sulfurization of a fatty acid ester, such as sperm oil, is conducted at temperatures between 90 and 120 F., preferably between 50 and 90, F., with the slow addition of sulfur chloride to the sperm oil at such a rate that the increase in temperature is not excessive. In order to prevent any substantial increase in temperature due to the exothermic heat of'reaction, special cooling means are employed, or if no special cooling means are provided, the sulfur chloride is added at such a slow rate in order to avoid excessive exothermic heat of reaction. This usually requires a period of from two to five hours.

It is an object of the present invention to provide an improved method of sulfurizing un-' saturated mono-esters of'aliphatic acid to ob tain. a product of good color and high sulfur content.

Another object of the invention is to provide a rap 1 n ethod of sulfurizing unsaturated monoesters of aliphatic acids.

y it. still further object of the invention is to proproved method of reacting unsaturated :neno eeters of aliphatic acids with a sulfur chloride which will enable the reaction to rapidly take without the formation of dark color sulfurized products.

[mother object of the invention is to provide an improved method of reacting sperm oil with a sulfur chloride which will result in a sulfurized sperm oil of improved color and stability.

Another object is to provide an improved meth- 0d of reacting tall oil esters with sulfur chloride toobtain sulfurized products of improved color, Oder, etc. I [v Other objects and advantages of the invention will become apparent from the following description thereof. j In accordance with the present inventionsulf furized "unsaturated mono=esters or aliphatic acids of light color and of good'odor are 'ob tained by subjecting such mono-esters to I re action with a sulfur chloride in the presence of water as hereinafter described.

The unsaturated mono-esters of aliphatic a'cids suitable for sulfurization according to the present invention are the unsaturated mono-esters of aliphatic acids having the following general formula:

in which R. is a hydrocarbon group selected from the class consisting of a straight chain aliphatic group and an unsaturated cycle-aliphatic group, It is a straight chain aliphatic. hydrocarbon group and X is oxygen or sulfur and mixtures of such esters. When R and R are both straight chain aliphatic groups, at least one is unsaturated prior to sulfurization and at leastone isof rela-e tiveiy high molecular Weightof at least about 8 carbon atoms, and preferably from about 10 to about 20 carbon atoms. When R is an unsaturated cyclo-aliphatic group it is preferably one of about 5 to 20 carbon atoms...

The term mono-ester as used herein and in the claims includes mono-esters derived from aliphatic alcohols and mono-thioesters derived from aliphatic mercaptans.

The mono-esters 'employedin the present ill-l vention can be pure mono-esters or mixtures of mono-esters. For example, suitable unsaturated esters are the mono-esters of unsaturated aliphatic mono vale'nt acids with saturated altphati'c monohydric alcohols or aliphatic mercaptans, and the mono-esters-of saturated aliphatic mono-basic acids with unsaturated monohydric alcohols or unsaturated aliphatic mercaptans. while the mono-ester of alcoholsof short aliphati'c chains, such asmethyl alcohol, ethyl a1- cohol, etc., with long chain aliphatic unsaturated acids can be used, it is preferable to use the mono-esters of long chain alcohols with long chain unsaturated acids. a I

Examples of specific mono-esters falling within the above formula are: I T

Allyl oleate Oleyl caprylate Decylene oleate I f llohyl linoleate Decylene thio-olea'te Oleyl ol'ea'te, Dodecylene oleate Ole'yl ,th'imoleate ctadecylene'eleate Ne 1T linoienate Dodecyl thio-oleate Nonyl abietate Methyl oleate Y Amyl linbleate Hexyl oleate rsoprop'yl abietate Lauryl oleate Nonyl ester of tall 'oil Dodecylene laurate I g The individual-mono-esters of the types above described or mixtures thereof, can be sulfurized in the manner herein described. An available source of mixed mono-esters is sperm oil which consists largely of mono-esters of the general formulain which 11 is at least 1, preferably 1 to 7.

The term unsaturated mono-ester of aliphatic acids as used herein and in the appended claims includes compositions composed of at least 50% of an unsaturated mono-ester of aliphatic acid or mixtures thereof, such as for example, esters of tall oil with an alcohol or a mercaptan. Tall oil contains about 50-55% unsaturated aliphatic acids, such as oleic acid, linoleic acid, and linole nic acid, and about 40% abietic acid.

Generally speaking, the sulfurization of the present invention is .accomplished by reacting the mono-ester of aliphatic acid with 5 to 50 volume per cent, and preferably to volume per cent of a sulfur chloride in the presence of 1 to 50 volume per cent, and preferably 5 to 20 VOlLLlIlB per cent, of added water, at a temperature of from about F. to about 250 F., and preferably about 120 F. to about 160 F., for a period of from about 0.25 hour to 2 hours, and preferably from about 0.5 hour to one hour.

In carrying out the sulfurization, I prefer to add the sulfur chloride and water simultaneously but separately to the ester. However, the ester can be sulfurized by adding the sulfur chloride to a mixture of the ester and water or the ester may be added to the mixture of sulfur chloride and water. In the former case, the sulfur chloride should be added slowly, while in the latter case precaution should be taken to provide adequate cooling since the reaction is vigorous. The sulfurization may be carried out by adding water to a mixture of sulfur chloride and the ester; how: ever, the sulfurized product may be darker than that obtained in the other variations. In the preferred order of adding the reactants, the sulfur '1 chloride addition can be completed in about 10 to 20 minutes. The sulfur chloride employed may be any of the usual sulfur chlorides, such as sulfur mono-chloride (S2012), sulfur dichloride ($012) or mixtures thereof.

The sulfurized product obtained in the manner described contains some so-called corrosive sulfur and chlorine, and for uses wherein the presence of corrosive sulfur and chlorine is not detrimental or objectionable the product obtained in the sulfurization reaction can be used as such, after neutralization with an alkaline reagent such as an alkali metal or alkaline earth oxide, hydroxide or carbonate, for example NaOI-I, NazCOz, CaO, K2003, etc. The alkaline reagent is preferably added in solid form, although solutions thereof can be used. The neutralized product can then be taken up in a low-boiling hydrocarbon solvent such as hexane, naphtha, etc., separated from the hydrocarbon insoluble products and recovered by evaporation or distillation of the solvent.

If the presence of corrosive sulfur is objectionable, or detrimental to the intended use of the sulfurized product, the latter can be freed of the corrosive sulfur by subjecting the same to a socalled deactivation step. To obtain a non-corrosive product, the sulfurized product, either after neutralization as above described, or without lization, is refluxed with a solution prior neutra containing about 5 per cent to about per cent of an alkali metal sulfide, such as sodium sulfide, a low molecular weight aliphatic alcohol, such as isopropyl alcohol, ethyl alcohol, butyl alcohol, and the like, and water. The solutions are refluxed. for a period of from about one hour to about five hours and preferably for about three hours. A suitable deactivating solution is one containing about 18 grams of anhydrous sodium sulfide, 34 cubic centimeters of isopropyl alcohol, and cubic centimeters of Water for each 100 grams of the sulfurized mono-ester fatty acid. Deactivation of a previously neutralized sulfurized product can be accomplished by refluxing the entire neutralized reaction mass with the alcoholic solu-- tion of the alkali metal sulfide without separating the neutralized hydrocarbon soluble fractions from the insoluble fractions. After refluxing, for the desired period, an equal volume of a low boiling hydrocarbon solvent, such as hexane or a low boiling naphtha, such as a petroleum naphtha boiling below 360 F., is added, if necessary, to the refluxed solution and the mixture allowed to settle for several hours to permit stratification into two distinct layers, the upper containing the deactivated sulfurized product. The deactivated product is recovered by distilling off the hydrocarbon diluent or by other suitable means. The deactivation step also removes chlorine from the sulfurized product, the extent of de-chlorination being dependent upon the amount of deactivator, i. e. NazS, a sulfurized product substantially free of chlorine can be obtained.

The herein described improved method of sulfurizing monoaliphatic esters will be readily understood from the following examples which are given by way of illustration and are not intended as limitng the scope of the invention.

EXAMPLE I Sperm oil was treated with 50 volume percent sulfur chloride and 25 volume percent water from separate containers with constant stirring for a period of 60 minutes at a temperature of about 159 F. to about 220 Ice water was used to cool the reaction mixture when necessary to maintain the desired temperature. The sulfurized sperm oil was then neutralized with solid sodium carbonate, taken up in hexane, and finally recovered by evaporation of the hexane diluent. The recovered sulfurized product had a true color of 600, a sulfur content of 14.2% and a chlorine content of 7.6%.

EXAMPLE II Sperm oil was treated simultaneously with 30 volume percent sulfur chloride and 1'? volume percent water, added separately, at a temperature of from about F. to about 225 F. for a period of 90 minutes with constant stirring. At the end of the sulfurization time the reaction product was neutralized with about 1'7 by Weight sodium carbonate, and the neutralized product taken up in hexane; the hexane solution was then separated from the hexane insoluble material, and the hexane evaporated on a steam bath. The product recovered had a true color of 600, a sulfur content of 12.5% and a chlorine content of EXAMPLE III To the sperm oil there was added simultaneously, but separately, 18 volume percent sulfur chloride and 13 volume percent water, and the mixture maintained at a temperature of 93 F. to 172 F. for a period of 45 minutes. At the end of this period the reaction mass was neutralminutes.

ized by adding thereto Weight percent of solid sodium carbonate and the neutralized mass taken up in hexane. separated from the hexane insoluble material, and the hexane evaporated on a steam bath; the

The hexane solution was then product obtained had a true color of 368, a sulfur content of 11.6% and a chlorine content of 7.4%.

EXAMPLE IV sperm oil was treated simultaneously with 16 volume percent sulfur chloride and 10 volume percent Water at a temperature of 84 F. to

120 F. for a period of 60 minutes, At. theend of the sulfurization time the reaction product was neutralized with weight percent solid sosulfurized sperm oil obtained above described, with the exception that no added water was employed; had a true color of 300, a sulfur content of 10.1% and a chlorine content of 0.7%.

" EXAMPLE V Simultaneously but separately, there were added to sperm oil 8% (vol.) S2012 and 8% (VOL) -water,- and the mixture maintained at a maximum temperature of about 145 F. for a period of about minutes. The reaction mass was then refluxed with a 17% solution of sodium sulhole for 1-2 hours at a temperature of 155 F.- 195 F. A mixture of hexane and isopropyl alcohol was then added and the mixture permitted to separate into two layers. layer containing the sulfurized product was then separated and the hexane removed by evaporation. The sulfurized product had a true color of less than 29, a sulfur content of 4.9%, and a chlorine content of 2.5%.

EXAMPLE VI Methyl oleate was treated with 16 volume percent sulfur chloride and 10 volume percent water at a temperature of 120 F.- 160 F. for about The, reaction mass was then neutralized with 15 weight percent sodium carbonate, the neutralized producttaken up in hexane, and the hexane soluble fraction separated from the insoluble fraction. The hexane was removed by evaporation on a steam bath. The recovered product. had a sulfur content of 9.4%, a chlorine content'of 6.9%;and a true color of 18. o v The same procedure. but withoutwater, yielded a-product of 9.9% sulfur, 7.9% chlorine, and

a true color of 75.

EXAMPLE VII A tall oil ester of oleyl alcohol was prepared in the usual manner by esterifying a tall oil with an excess of the oleyl alcohol using sulfuric acid as a catalyst, and petroleum naphtha as the solvent.

The ester formed was sulfurized at a temperature'of-122 F. to. 175 F. with about 30 weight The product obtained had a true color of 1 about 75, a sulfur content of 10.5% and a chlorine content of-1.6%.

in the manner The upper hexane I "e percent sulfur chloride and 10 volumepercent water; the sulfur chloride and water being added simultaneously but separately, to the tall oil ester. The reaction mixture was maintained at the aforesaid temperature for about minutes and then neutralized with about 15 weightpercent solid sodium carbonate. Theneutralized product was then taken up in hexane and the hexane solution separated from the hexaneinsoluble material and thehexane evaporated on a steam bath. The sulfurized material had a truec'olor of 464, a sulfur content of 11.4% and a chlorine content of 6.5%

EXAMPLE VIII A tall oil ester of nonyl alcoholwas prepared in the usual manner by esterifying a tall oil with an excess of the nonyl alcohol using alkane sulfonic acid as a catalyst and petroleum naphtha as a solvent. I

The ester so obtained was sulfurized at a temperature of 122 F. to 175 F. with about 30 weight percent sulfur chloride and 10 volume percent waterfor, a period of about 60 minutes. The

' sulfur chloride and water were added simultaneously but separately to the tall oil ester. At the end of the sulfurization period the reaction mass was neutralized with about 15 weight percent solid sodium carbonate, taken up in hexane and the hexane soluble portion separated from the hexane insoluble portion. The product, after evaporation of the hexane, had a true color of 300, a sulfur content of 10.4 and a chlorine content of 4.0%. EXAMPLE IX The sulfurized tall oil ester of Example VIII was deactivated byrefiuxing the same with an alcoholic solution containing about 16-18% sodium sulfide at a temperature of 167 F. to 194 F. for a period of 180 minutes. The refluxed material was then taken up with hexane, the hexane solution separated from the hexane insoluble material and the hexane evaporated from the hexane solution. The deactivated product had a true color of 184, a sulfur content of 7.6% and a chlorine content of 0.2%.

EXAMPLE X The nonyl ester of tall oi1 sulfurized in a manner as described in Example VIII, except that no water was used in the sulfurization step. The product obtained had a true color of 736, a sulfur content of 11 .4 and a chlorine content of 4.2.

The improvement obtained in sulfurizing mono-esters of aliphatic acids with sulfur chloride in the presence of water in accordance with the present invention is demonstrated bythe data tabulated in Table I. These data were obtained I by sulfurizing sperm oil in a manner herein-before described, using various amounts of sulfur chloride, water, and the corresponding sulfuriza-,

tions being carried out in the absence of added water.

Table I SzClz H20 1 Percent Percent True Run N0 Parts, Parts, .Sulfur Chlorine Color 30 o 14. 2 10. e 3, s40

.1 Based on volume partsof sperm oil.

The above data illustrate that sulfurized products of much lighter color are obtained by carrying out the sulfurization in the presence of water than is obtained without the addition of water. The true color value reported herein is obtained by determining the dilution necessary to get an ASTM color between 4 to 5 by using a colorless diluent, e. g. naphtha, and calculating the true color according to the following table.

ASTM color Dilution Ratio 5 4% 4% 4% 4 1 Samplmsample plus diluent. The true color can be calculated according to the formula: 'Irue color=ASTM color at a dilution of 1:1 times the dilution required to give an AS'IM color equivalent to a 1:1 diluted product. In the above table the true color values for 1: 1 dilution corresponding to ASTM colors for 4 to 5 are obtained from the chart on page 155 of Industrial and Engineering Chemistry, February 1926.

Comparative data on the sulfuriza-tion of tall oil esters are tabulated in Table II. The sulfuri zation of the esters was carried out by treating the ester with the sulfur chloride in the presence of 10% by volume of water at a temperature of 122 F. to 175 F. for about 60 minutes, neutralizing the reaction mass with by weight of solid sodium carbonate and recovering the sulfurization product by extraction with hexane in the manner hereinbefore described.

The above data show improvement obtained in color by carrying out the sulfurization of tall oil esters in the presence of water. The data also illustrate that deactivation of a sulfurized product with sodium sulfide not only improves the color of the product but also produces a noneorrosive material.

In addition to providing a method of obtaining a sulfurized mono-ester of improved color, the process of the present invention makes it possible to produce sulfurized esters of relatively low viscosity compared to the viscosity of sulfurized esters obtained in the absence oi water. This is demonstrated by the data presented in Table III. Sulfurized sperm oil, run 1, was obtained by reacting sperm oil with 16 volume percent sulfur chloride and 10 volume percent of water at a maximum temperature of 152 F. for eighteen minutes, followed by one hour stirring and by the neutralization with 15 weight percent of solid sodium carbonate. The neutralized product was then taken up into hexane and recovered as here- 8 inbefor described. The sulfurized sperm oil of run No. 2 was obtained by reacting sperm oil with 16 volume percent sulfur chloride, in the absence of water, at a maximum temperature of about 151 F. for 18 minutes, followed by one hour stirring.

The sulfurized mono-esters of the present invention are soluble in hydrocarbon oils, such as for example, natural mineral lubricating oils and synthetic hydrocarbon lubricating oils, and when compounded with such oils are effective in imparting extreme pressure properties thereto. The extreme pressure properties imparted to such lubicating oils is shown by data in Table IV, in which tests on the Timken and Almen machines are tabulated. These data were obtained on a blend of of a mineral lubricating oil having a SUS viscosity at F. of about seconds and 10% sulfurized sperm oil and sulfurized tall oil esters; the sulfurization being carried out in accordance with the present invention.

As is demonstrated by the foregoing data the method of sulfurizing unsaturated mono-esters of aliphatic acids by the sulfurization with sulfur chloride and added water in the manner herein described provides a facile process for obtaining such sulfurized products of very good color and relatively low viscosity.

The sulfurization of substantially saturated oxygenated aliphatic compounds with a sulfur chloride in the presence of water and in the absence of added hydrogen sulfide is described and claimed in my copending application Serial No. 107,822, filed July 30, 1949. The sulfurization of unsaturated fats and fatty acids with a sulfur chloride in the presence of water and in the absence of added hydrogen sulfide is described and claimed in my copending application Serial No. 108,856, filed August 5, 1949.

While I have described in detail preferred embodiments of my invention, it should be understood that the invention is not limited to any of the details herein above set forth, but includes within its scope such modifications as come within the spirit of the appended claims.

I claim:

1. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the general formula in which R is a hydrocarbon group selected from the class consisting of a straight chain aliphatic aro ene gr up and an un aturated yclo aliphati group, R. is a straight cha n aliphati hyd carbon group. and X is select d f om the stone consis ing of sulfur and oxygen, and wherein when R and R, are both straight chain aliphatic groups, at least one is unsaturated, and at least one contains at least 8 carbon atoms and mixtures of said esters, comprising reacting said ester with a sulfur chloride and from about per cent to about 50 per cent by volume of water free of ammonia at a temperature of from about 40 F. to about 250 F. in the absence of added hydrogen sulfide.

2. The method of sulfurizing an unsaturated mo st r of an aliphatic acid having the neral formula in which R, and R are straight, chain aliphatic hydrocarbon groups, X is selected from 171 .8 group consisting of sulfur and oxygen, wherein at least one of the aliphatic groups is unsaturated and at least one contains at least 8 carbon atoms, and mixtures of said esters, comprising reacting said ester with sulfur chloride, and from about 5 per cent to about 50 per cent by volume, of water free of ammonia at a temperature of from about 40 F. to about 250 F. in the absence of added hydrogen sulfide.

3. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the general formula in which R and R are unsaturated straight chain aliphatic hydrocarbon groups, and X is selected from the group consisting of oxygen and sulfur, comprising reacting said ester with a sulfur chloride and from about 5 per cent to about 50 per cent by volume of water free of ammonia at a temperature of 40 F. to'about 250 F. in the absence of added hydrogen sulfide.

4. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the genin which y is at least 1, comprising reacting said ester with a sulfur chloride and from about 5 per cent to about 50 per cent by volume of water free of ammonia at a temperature of from about 40 F. to about 250 F. for a period of from about 15 minutes to about 120 minutes, in the absence of added hydrogen sulfide.

5. The method of sulfurizing sperm oil comprising reacting sperm oil with sulfur chloride and from about 5 per cent to about 50 per cent by volume of water free of ammonia at a temperature of from about 40 F. to about 250 F., in the absence of added hydrogen sulfide.

6. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the general formula in which R. is an unsaturated eyclo-aliphatic hydrocarbon group of from about 5 to 20 carbon atoms, X is selected from the group consisting of sulfur and oxygen and R is a straight chain aliphatic hydrocarbon group, comprising reacting said ester with a sulfur chloride and from abou er ent to a ou O er cent, by volume,

ter tree of a iin'loniav at a temperature of from,

F. to about 250 F. in the absence of added hydrogen sulfide. 1 1

8. The method of claim 7 in which the tall oil ester isa nonyl ester of tall oil.

9. The method of sulfurizing perm oil comprisingreacting sperm oil with from about 10 per cent to about 30 per cent, by" volume, of a sulfur chloride, and from about 5 per cent to about 20 per cent, by volume, of water free of ammonia at a temperature of: about 120 F. to about160 F.,

,"for a periodof from about 15 minutes to about 60 minutes, the sulfur chloride and water being added slowly simultaneously but separately, said sulfurization being carried out in the absence of added hydrogen sulfide.

10. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the general formula l n whic R a hydrocarbon gr u s ected. from he cla s. i ti of a. straight chain a iphatic r up. nd. anunsa urated alioy ic roup. R s a strai ht cha n. aliphatic r up, nd is selected from he gr up con sting of xygen. and s lfur, and wherein when, R and R are both strai ht c n a iphatic roups, a east o e is unsaturated nd at ea t one containsat least fi oar on, a ms comprising reactingsaid ester with a sulfur chloid and from about 5. P r en to abou 5. p r cent, by volume, o wa er fre o ammonia at a mperature of from. about o about 250 in the absence of added hydrogen sulfide, and e aliz n h suliurized produ t with a alkaline reagent.

11. The method of claim 10 in which the alkaline reagent is an alkali metal carbonate.

12. The method of claim 10 in which the alkaline reagent is sodium carbonate.

13. The method of claim 10 in which the alkaline reagent is an alkali metal sulfide.

14. The method of claim 10 in'which the alkaline reagent is sodium sulfide. 15. The method of sulfurizin unsaturated mono-esters of aliphatic acids having the general formula in which R and R are straight chain aliphatic groups, X is selected from the group consisting of sulfur and oxygen, and wherein at least one of the aliphatic groups is unsaturated and at least one contains at least 8 carbon atoms, and mixtures of said esters, comprising reacting said esters with sulfur chloride, and from about 5 per cent to about 50 per cent by volume of Water free of ammonia at a temperature of from about 40 F.

. to about 250 F., in the absence of added hydro- 1 1 16. The method of sulfurizing unsaturated mono-esters of aliphatic acids having the general bon atoms, and mixtures of said esters, comprising reacting said esters with a sulfur chloride and from about 5 per cent to about 50 per cent by volume of water free of ammonia at a temperature of from about 40 F. to about 250 F., in the absence of added hydrogen sulfide, neutralizing the sulfurized product with an alkali metal carbonate, refluxing the neutralized product with an alcoholic solution of an alkali metal sulfide and recovering the sulfurized ester by extraction with a hydrocarbon solvent.

17. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the genin which R and R are unsaturated straight chain aliphatic hydrocarbon groups, and X is selected from the group consisting of oxygen and sulfur, comprising reacting said ester with a sulfur chloride, and from about 5 per cent to about 50 per cent, by volume, of water free of ammonia at a temperature of 40 F. to about 250 F., in the absence of added hydrogen sulfide, neutralizing the sulfurized product With an alkaline reagent, adding a low-boiling hydrocarbon solvent to the neutralized reaction mixture and separating the hydrocarbon-soluble fraction from the hydrocarbon-insoluble fraction.

18. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the general formula in which y is at least 1, comprising reacting said ester with a sulfur chloride and from about 5 per cent to about 50 per cent, by volume, of water free of ammonia at a temperature of from about 40 F. to about 250 F. in the absence of added hydrogen sulfide, for a period of from about minutes to about 120 minutes, neutralizing the sulfurized product with an alkaline reagent, adding a low- 12 boiling hydrocarbon solvent to the neutralized reaction mixture and separating the hydrocarbonsoluble fraction from the hydrocarbon-insoluble fraction.

19. The method of sulfurizing sperm oil comprising reacting sperm oil with sulfur chloride and from about 5 per cent to about 50 per cent, by volume, of water free of ammonia at a temperature of from about F. to about 250 F., in the absence of added hydrogen sulfide, said sulfur chloride and Water being added to said sperm oil simultaneously but separately, neutralizing the sulfurized product with an alkaline reagent, adding a low-boiling hydrocarbon solvent to the neutralized reaction mixture and separating the hydrocarbon-soluble fraction from the hydrocarbon-insoluble fraction.

20. The method of sulfurizing an unsaturated mono-ester of an aliphatic acid having the genin which R. is a hydrocarbon group selected from the class consisting of a straight chain aliphatic group of from 1 to about 20 carbon atoms and an unsaturated cycle-aliphatic group of from about 5 to 20 carbon atoms, R is a straight chain aliphatic group of from about 1 to 20 carbon atoms, and X is selected from the group consisting of sulfur and oxygen, and wherein where R and R are both straight chain aliphatic groups, at least one is unsaturated and at least one contains at least 8 carbon atoms, comprising reacting said ester with a sulfur chloride and from about 5 per cent to about per cent, by volume, of water free of ammonia at a temperature of from about F. to about 250 F., in the absence of added hydrogen sulfide, neutralizing the suliurized product with a solid alkaline reagent, adding a low-boiling hydrocarbon solvent to the neutralized reaction mixture, separating the hydrocarbon-soluble fraction from the hydrocarbondnsollsble fraction and refluxing the hydrocarbon-soluble fraction with an alcoholic solution of an alkali metal sulfide.

HELEN SELLEI BERET V AS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,218,997 Wasson Oct. 22, 1940 2,257,290 Voorhees Sept. 30, 1941 2,289,438 Knowles Jul 14, 1942 2,313,611 Abramowitz Mar. 9, 1943 2,337,473 Knowles Dec. 21, 1943 2,417,283 Zimmer Mar. 11, 1947 

1. THE METHOD OF SULFURIZING AN UNSATURATED MONO-ESTER OF AN ALIPHATIC ACID HAVING THE GENERAL FORMULA 